Slide-fastener stringer

ABSTRACT

A slide-fastener stringer has two support tapes to whose confronting edges are stitched respective interleavable coupling elements. Each coupling element is a continuous synthetic-resin monofilament of helical or meandering shape forming a multiplicity of integrally interconnected links each having a pair of shanks connected together at one end by a coupling head and each connected at the other end by a respective bight to a shank of a neighboring link. One or both shanks of each link are provided with at least one laterally projecting barb formed by partially chipping a longitudinal sliver from the monofilament, without completely severing it from the body thereof, bending that sliver transversely outwardly and thermofixing it in this position. The stitching securing each link to the tape is locked in place by passing between this barb and the connecting bight. Other such barbs may bite into the fabric of the tape to help hold the coupling element in position.

United States Patent 1 1 Heimberger SLIDE-FASTENER STRINGER [75] Inventor: Helmut Heimberger,Grenzach,

Germany [73] Assignee: Opti-l-Iolding AG, Glarus,

Switzerland [22] Filed: Aug. 21, 1972 [21] Appl. No.: 282,553

[30] Foreign Application Priority Data Aug. 20, 1971 Germany 2141687 [52] us. CI 24/205.1 C, 24/2Q5.13 C, 24/205.16 C [51] Int. Cl A44b 19/12 [58] Field of Search 24/205.13 C, 205.1 C, A .U..s.. 6 C

[56] References Cited UNITED STATES PATENTS 3,022,803 2/1962 Berberich 24/205.l3 C 3,248,767 5/1966 Hansen 24/205.l3 C

3,266,114 8/1966 Gerlach 24/205.1 C 3,772,743 11/1973 Hansen 24/205.l3 D

FOREIGN PATENTS OR APPLICATIONS 240,672 9/1962 Australia 24/205 13 C 874,494 8/1961 Great Britain 24/205.13 C 213,471 6/1967 Sweden 24/205.l C

Primary ExaminerBemard A. Gelak Attorney, Agent, or Firm-Karl F. Ross; Herbert Dubno [57] ABSTRACT A slide-fastener stringer has two support tapes to whose confronting edges are stitched respective interleavable coupling elements. Each coupling element is a continuous synthetic-resin monofilament of helical or meandering shape forming a multiplicity of integrally interconnected links each having a pair of shanks connected together at one end by a coupling head and each connected at the other end by a respective bight to a shank of a neighboring link. One or both shanks of each link are provided with at least one laterally projecting barb formed by partially chipping a longitudinal sliver from the monofilament, without completely severing it from the body thereof, bending that sliver transversely outwardly and thermofixing it in this position. The stitching securing each link to the tape is locked in place by passing between this barb and the connecting bight. Other such barbs may bite into the fabric of the tape to help hold the coupling element in position.

6 Claims, 9 Drawing Figures MENU-3652241974 sum 2 OF 2 F|G.7B

BENDING BACK THERMOFIXING SLlDE-FASTENER STRINGER FIELD OF THE INVENTION My present invention relates to a slide-fastener stringer half with integrally interconnected links having coupling heads matingly engageable with those of a substantially symmetrical element, these links being constituted by a unitary coupling element of syntheticresin monofilament stitched to a supporting tape.

BACKGROUND OF THE INVENTION One of the principal difficulties in the manufacture of slide-fastener stringers having unitary coupling elements of meandering or helical shape is retaining these elements securely on the edge portions of their respective support tapes. Coils or meanders of monofilamentary resin are very smooth and often cannot be held in position on the tape by friction alone.

In order to overcome this difficulty, recourse has been had to forming notches or depressions in the coupling elements, with the stitching lying in these incisions. If the notches are deep enough to prevent disengagement of the stitching, they may greatly weaken the coupling elements; this is particularly serious in the case of narrow-gauge slide fasteners having very thin coils as their coupling elements.

OBJECTS OF THE INVENTION It is therefore an object of my present invention to provide an improved slide-fastener stringer half of the character referred to which overcomes the abovedescribed disadvantages.

Another object is to provide such a coupling element with a configuration enabling its stable positioning on an associated stringer tape.

SUMMARY OF THE INVENTION These objects are attained, in accordance with my present invent-ion, by providing the body of a helical or meandering coupling element of monofilamentary synthetic resin (e.g. polyamide) at some or all of its unitarily interconnected links with one or more integral barbs projecting laterally therefrom. These barbs serve as locators co-operating with the stitching in fixedly securing the monofilamentary body to its supporting stringer tape, as by engaging the stitching loops and/or by penetrating into meshes of the tape fabric. The barbs may also be confrontingly disposed on adjacent links to maintain a predetermined minimum spacing therebetween; they may further serve as abutments for the opposite coupling heads to limit the extent of interpenetration of the links of the two mating coupling elements.

According to another aspect of my invention, each barb is formed by partially chipping a longitudinal sliver from the side of the monofilament while leaving that sliver connected at one end to the body of the coupling element. The sliver is then bent generally perpendicularly outwardly and thermally fixed in its transverse position, advantageously at the same time that the entire body is stabilized by such heat treatment.

With this mode of manufacture, only a shallow longitudinal depression of a shape substantially complementary to that of the barb is left in the surface of the monofilamentary body adjacent that barb. The latter retains the molecular orientation (in the direction of its length) originally imparted to the resinous body by mechanical working.

BRIEF DESCRIPTION OF THE DRAWING The above and other features of my invention will now be described in detail with reference to the accompanying drawing in which:

FIG. 1 is a top view of a slide-fastener stringer according to the present invention;

FIG. 2 is a top view of two interleaved coupling elements forming part of the stringer of FIG. 1;

FIG. 3 is a cross-sectional view taken along line III- III of FIG. 2;

FIG. 4 is a view similar to FIG. 2 but showing a pair of modified coupling elements;

FIG. 5 is a cross-sectional view taken along line V-V of FIG. 4;

FIG. 6 is a cross-sectional view similar to FIGS. 2 and 4, illustrating a further modification; and

FIGS. 7A-7C show successive steps in the formation of a coupling element according to my invention.

SPECIFIC DESCRIPTION As seen in FIGS. 13, a slide-fastener stringer comprises a pair of generally helical coupling elements 1 secured to edge portions of respective support tapes 2 by means of stitching 3. Each coupling element 1 consists of a multiplicity of links 4 each including an upper shank 4a remote from the tape surface, a lower shank 4b lying on the tape, a front bight 4c formed as a coupling head, and a back bight 4d connecting each link 4 to a neighboring link. The shanks 4a and 4b are generally perpendicular to the longitudinal coupler axis 8 (FIG. 2).

Each upper shank 4a is formed, at a location set back from its coupling head 40, with an integral barb 5' projecting laterally therefrom substantially parallel to axis 8. These barbs 5' engage the stitching 3 looped around the rear part of each link 4 so that the knot formed by the two-thread double-locked stitch (Federal Standard type 401) is securely contained on all four sides between the barbs and the back bights 4d. Since the top of the stringer is left free of any stitch-retaining formations, the danger of catching on the wearers garments is greatly reduced.

In addition, as shown in FIG. 2, the sliver-like barbs 5 function as abutments for the opposite coupling heads, thereby limiting the interpenetration or overlap 6 of the mating links of the two elements 1. They also serve to define the interlink spacing 7 (FIG. 4) by virtue of their confronting disposition on adjoining links 4, two aligned barbs being provided for this purpose on each upper shank 4a (see also FIG. 5).

As shown in FIG. 6, the lower shanks 4b may be provided with similar barbs 5" which penetrate into the textile tapes 2 and prevent creeping of the coupling element 1 thereon This requires, of course, that the barbs 5" be so oriented as to point downwardly into the tapes; FIGS. 5 and 6 also clearly show a similar downward pointing of the upper barbs 5' to avoid any risk of entanglement with the garments of the wearer as mentioned above.

The upper and lower barbs 5', 5" have the same orientation relative to the monofilamentary body from which they are cut by the same process, described below, which leaves a shallow depression 11 adjacent each barb. This depression is not so deep as to result in an appreciable weakening of the monofilament, even where the latter is of small diameter. The same would be true if the monofilamentary body 1 were of meandering shape, rather than helicoidal as shown.

FlGS. 7A7C show how a blade 9, which may be part of the coil-forming equipment, is brought into engagement with the monofilament to cut therefrom a sliver 5'. In FIG. 781 have shown how the sliver 5 so formed is then bent back to project at a right angle from the monofilament body. Finally, as illustrated in FIG. 7C, a heat lamp 10 irradiates the resulting barb 5' to stabilize it by a thermofixing operation of the type conventionally employed in the production of slide fasteners of this nature.

I claim: I

l. A slide-fastener half comprising:

a stringer tape;

a coupling element of continuous synthetic-resin monofilament extending longitudinally on a surface of said tape, said element consisting of a multiplicity of integrally interconnected links each including a coupling head matingly engageable with a pair of similar coupling heads of a substantially symmetrical coupling element;

stitching securing said coupling element to said tape;

and

locator means on said coupling element co-operating with said stitching for securing said links to said tape in substantially fixed positions, said locator means including a plurality of elongate barbs on at least some of said links set back from said coupling heads, said barbs projecting integrally from the monofilamentary body of said element, each barb being a sliver partly severed from said body whereby a shallow longitudinal depression is formed adjacent the barb and substantially complementary to the shape thereof, the barb having the same molecular orientation as said body upon being bent back into the adjacent depression but being stabilized in position to resist being thus bent back.

2. A slide-fastener half as defined in claim 1 wherein said links have shanks extending generally transversely to the longitudinal direction of said tape, the shanks of adjoining links being interconnected by bight portions remote from said coupling heads, said barbs being disposed on certain of said shanks at locations spaced from said bight portions and said coupling heads with an orientation making them point toward said tape.

3. A slide-fastener half as defined in claim 2 wherein said stitching forms loops around said certain of said shanks between said bight portions and said barbs.

4. A slide-fastener half as defined in claim 3 wherein said barbs of adjoining links extend toward each other for maintaining a predetermined minimum spacing therebetween.

5. A slide-fastener half as defined in claim 3 wherein said barbs form abutments for the coupling heads of the symmetrical coupling element, thereby limiting the extent of interpenetration of the links of the two coupling elements.

6. A slide-fastener half as defined in claim 2 wherein said tape is a fabric, said barbs penetrating into meshes of said fabric. 

1. A slide-fastener half comprising: a stringer tape; a coupling element of continuous synthetic-resin monofilament extending longitudinally on a surface of said tape, said element consisting of a multiplicity of integrally interconnected links each including a coupling head matingly engageable with a pair of similar coupling heads of a substantially symmetrical coupling element; stitching securing said coupling element to said tape; and locator means on said coupling element co-operating with said stitching for securing said links to said tape in substantially fixed positions, said locator means including a plurality of elongate barbs on at least some of said links set back from said coupling heads, said barbs projecting integrally from the monofilamentary body of said element, each barb being a sliver partly severed from said body whereby a shallow longitudinal depression is formed adjacent the barb and substantially complementary to the shape thereof, the barb having the same molecular orientation as said body upon being bent back into the adjacent depression but being stabilized in position to resist being thus bent back.
 2. A slide-fastener half as defined in claim 1 wherein said links have shanks extending generally transversely to the longitudinal direction of said tape, the shanks of adjoining links being interconnected by bight portions remote from said coupling heads, said barbs being disposed on certain of said shanks at locations spaced from said bight portions and said coupling heads with an orientation making them point toward said tape.
 3. A slide-fastener half as defined in claim 2 wherein said stitching forms loops around said certain of said shanks between said bight portions and said barbs.
 4. A slide-fastener half as defined in claim 3 wherein said barbs of adjoining links extend toward each other for maintaining a predetermined minimum spacing therebetween.
 5. A slide-fastener half as defined in claim 3 wherein said barbs form abutments for the coupling heads of the symmetrical coupling element, thereby limiting the extent of interpenetration of the links of the two coupling elements.
 6. A slide-fastener half as defined in claim 2 wherein said tape is a fabric, said barbs penetrating into meshes of said fabric. 